A federal judge says images such as these, if they were required by the U.S.… (Associated Press )

Reporting from Washington — A federal judge has blocked the government from requiring tobacco companies to begin placing images of diseased lungs and cadavers on cigarette packages, saying the health warnings violated the firms' 1st Amendment rights.

U.S. District Judge Richard Leon, in a 29-page ruling Monday, granted the preliminary injunction because he believed there was a "substantial likelihood" the cigarette companies ultimately would win "on the merits of their position that these mandatory graphic images unconstitutionally compel speech."

He also said that the images went beyond disseminating "purely factual and uncontroversial information" and ventured into advocacy.

The Food and Drug Administration rule, authorized by Congress in 2009 and slated to go into effect in September, now is likely to be embroiled in a legal dispute for months or years.

The images include an infant in an incubator, a man breathing through a respirator and a man breathing through a hole in his throat. Warnings such as "Tobacco smoke can harm your children" appear next to the images.

James Wheaton, a 1st Amendment expert who teaches at UC Berkeley and who has sued tobacco companies over what he says are inadequate warnings, agreed with the judge.

"You can't force a company to carry the government's opinion on an issue," Wheaton said. "These images are clearly not limited to a statement of fact. They're designed to evoke an emotional response."

But Matthew Myers, president of the Campaign for Tobacco-Free Kids, opposed weakening the warnings.

"There's an overwhelming case that these are constitutional and factually supportable," he said. "The judge was wrong on science, wrong on fact and ignored scientific evidence."

Myers cited studies, such as one completed by Canada's University of Waterloo in May, showing that large, graphic images are most effective at getting the attention of young people and thus should be a permissible way to inform the public.

Rep. Henry Waxman, a Democrat, expressed confidence that the FDA ultimately would be permitted to require the graphic warnings.

He said that Congress, in giving the FDA the go-ahead on its plan to require the images, "considered the 1st Amendment issues involved and carefully tailored the legislation to ensure the FDA could act" as it proposed. He predicted the FDA rule would "be affirmed and permitted to go into effect next year."

The FDA declined to comment on the ruling.

Wheaton said some of the FDA labels — such as one with pictures of healthy lungs next to diseased lungs — might be considered to be based on fact and therefore would have a better chance of passing constitutional muster.

Besides the images themselves, the tobacco companies are unhappy about the amount of space the warnings would take up on their packaging.

"You have to draw the line somewhere," Wheaton said. "You can't tell them the whole box will be a warning label with a logo in the corner. The smoking companies don't come into this with clean hands either, but that doesn't mean you can take away their constitutional rights."